/*
 * #%L
 * What is Defensive Copying
 * $Id:$
 * $HeadURL:$
 * %%
 * Copyright (C) 2012 - 2014 Java Creed
 * %%
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * #L%
 */
package com.javacreed.examples.oop.part3;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class Data {

  private final List<Integer> values = new ArrayList<>();
  private final List<Integer> immutableValues = Collections.unmodifiableList(values);

  public void addValue(final int value) throws IllegalArgumentException {
    if (value < 0) {
      throw new IllegalArgumentException("The value must be positive");
    }

    values.add(value);
  }

  public List<Integer> getValues() {
    return immutableValues;
  }

  @Override
  public String toString() {
    return String.valueOf(values);
  }
}
